Adamantanopyrimidine compounds and intermediates therefor

ABSTRACT

ADAMANTANOPYRIMIDINE COMPOUNDS OF THE FORMULAE:   1,9,12-TRI(R-),4-R&#34;,6-R&#39;&#39;-3,5-DIAZATETRACYCLO(5.3.3.1(9,12)   .0(2,7))TETRADEC-3-ENE (I)   1,9,12-TRI(R-),3-R&#34;,4-(O=),6-R&#39;&#39;-3,5-DIAZATETRACYCLO   (5.3.3.1(9,12).0(2,7))TETRADECANE (II)   USEFUL AS ANALGESIC, AND AS LOCAL ANAESTHETIC; AND INTERMEDIATES USEFUL IN THE SYNTHESIS OF THE FOREGOING ADAMANTANOPYRIMIDINO CMPOUNDS. IN THE ABOVE FORMULAE EACH R REPRESENTS HYDROGEN OR C1-C3 LOWERALKYL, THE SUM OF THE NUMBER OF CARBON ATOMS IN ALL THREE R GROUPS BEING NOT GREATER THAN 6; EACH R&#39;&#39; INDEPENDENTLY REPRESENTS HYDROGEN OR STRAIGH-CHAIN C1-C6 ALKYL; AND EACH R&#34; INDEPENDENTLY REPRESENTS HYDROGEN OR C1-C3 LOWERALKYL.

United States Patent US. Cl. 260-251 A 4 Claims ABSTRACT OF THE DISCLOSURE Adamantanopyrimidine compounds of the formulae:

useful as analgesics and as local anaesthetics; and intermediates useful in the synthesis of the foregoing adamantanopyrirnidino compounds. In the above formulae each R represents hydrogen or C -C loweralkyl, the sum of the number of carbon atoms in all three R groups being not greater than 6; each R independently represents hydrogen or straight-chain C C alkyl; and each R" independently represents hydrogen or C -C loweralkyl.

SUMMARY OF THE INVENTION The present invention is concerned with the preparation of certain adamantanopyrimidine compounds and with intermediates useful in their synthesis. The adamantanopyrimidine compounds, the ultimate products of the present invention, are of the formulae Patented Feb. 22, 1972 "ice In the above and succeeding formulae,

(1) each R represents hydrogen or C -C loweralkyl, the sum of the number of carbon atoms in all three R groups being not greater than 6;

(2) each R independently represents hydrogen or straight-chain C -C alkyl;

(3) each R" independently represents hydrogen or C -C loweralkyl;

(4) X represents The subject matter of the present invention can more readily be understood by reference to the following summary reaction scheme. In this reaction scheme, as generally herein, the symbol Ad is employed to designate a 1,2 divalent adamantyl radical of the formula and the symbol Ad, to designate a 1,2,2 trivalent adamantyl radical of the formula this column: this column: W

Section I Section III F i r i l CH-C-OH CHC--0H Ag Ag O NH-R" i /CHC-halogen Ad if JH-CNHi /CH-C-NH2 AQ e Ag o NHR this column: 1

SeetlonII r i CHNH--CR" (EH-NH:

Ad Ad a i CH-NH-C-R" /OH-NH2 Ad Ad NE NH NHR K (J N I ll! 1'1 Formula-II "3 NH Ad I FormulaI DETAILED DESCRIPTION OF THE INVENTION Throughout the present invention, compounds are named in accordance with standard chemical nomenclature. Thus, those compounds in which the adamantane ring is the only cyclic units are named as substituted admantanes, e.g., 2-amino-l-adamantaneacetic acid. Those compounds in which the adamantane ring is fused to the pyrimidine ring are named as tetracyclic compounds. For example, the compound of Formula II in which all R, R, and R" symbols designate hydrogen:

inabove, the present invention is concerned ultimately with the preparation of compounds which can be described generically as adamantanopyrimidine compounds, the compounds of Formulae I and II. However, for the purpose of the following discussion, the various reactions are sub-divided into sections I, II, and III, as indicated hereinabove in the summary reatcion scheme.

Section I In accordance with this section, a 2-keto-1-adamantaneacetic acid:

is converted to the corresponding acyl halide:

The conversion can be accomplished in any of the known procedures for conversion of an acid to an acyl halide. Most typically, the acid is reacted with a phosphorus halide, preferably, thionyl halide. Excess reagent or typical solvents, such as the hydrocarbons, can be used as an inert liquid reaction medium; the reaction goes forward at temperatures over a wide range, such as from room temperature or below to 100 C. or higher. Work-up is carried out in conventional procedures.

The resulting acyl halide is then converted to the corresponding amide:

in known procedures for conversion of acids to amides. Thus the acid is reacted with ammonia, in the form of aqueous ammonia or as gaseous dry ammonia. Hotfmann degradation of the resulting amide yields the corresponding amine:

The keto group of this amine compound is then reductively aminated by reaction wtih an amine of the formula NH R" to obtain the corresponding Z-amino-l-adamantanemethylamine:

NH-R

Reductive amination is accomplished in accordance with procedures well known in the prior art for this reaction. Thus in the foregoing procedure are prepared all of the intermediates of Section I.

Section II In accordance with Section II, various procedures are utilized to obtain the ultimate products of the present invention which are of Formula I.

Initially, a 2-keto-l-adamantanemethylamine RI I C H-N H2 prepared as discussed in Section I, is acylated by reaction with an acyl halide of the formula to yield the corresponding Z-keto-N-acyl-l-adamantanemethylamine:

This intermediate, in turn, is reductively aminated with ammonia, affording the corresponding 2-amino-N-acyl-1- adamantanemethylamine:

This intermediate is then cyclized to obtain the ultimate products of the present invention which are of Formula I:

Cyclization can be efiected by treatment with a base.

Thus, in this method are prepared the various intermediates involved in Section II, as well as the ultimate products of Formula I.

Section III NH-R The amine moiety thereof is protected, such as by reaction with benzyl chloroformate, and the acid group of the resulting compound R t b1-1 o on Ad R protecting group converted to the acyl chloride and then aminated with ammonia and the amino protecting group removed. As a result of these operations, there is obtained the corresponding 2-amino-l-adamantaneacetamide:

t UIF-NH; i

NHR

Alternately, this compound can be prepared by reductive amination of 2-keto-l-adamantaneacetamide, which compound is described hereinabove in Section I. Regardless of the method by which it is prepared, the Z-amino-ladamantaneacetamide is then cyclized to the ultimate product of the present invention, of Formula II:

\12R13 9 7NII Cyclization is effected by subjecting the 2-amino-1- adamantane-acetamide to Hotfmann rearrangement conditions.

Thus in the manners described foregoing are prepared all of the ultimate products and intermediates of the present invention.

The ultimate products of the present invention which are of Formula I are readily reacted with acids in standard procedures to form corresponding acid addition salts. Particularly suited for the practice of the present invention are pharmaceutically acceptable acid addition salts. Such salts include the chloride, bromide, iodide, sulfate, bisulfate, acetate, salicylate, valerate, laurate, benzoate, phosphate, and the like.

The following examples illustrate the present invention and will enable those skilled in the art to practice the same.

EXAMPLE 1 2-keto-l-adamantaneacetyl chloride 2-keto-l-adamantaneacetic acid (5.0 grams; 0.024 mole) was dissolved in thionyl chloride ml.) and the solution was heated under reflux for 1 hour. Excess thionyl chloride was removed under vacuum and the residue was dissolved in dry benzene and again evaporated under vacuum to obtain the desired 2-keto-l-adamantaneacetyl chloride as a residue.

EXAMPLE 2 2-keto-l-adamantaneacetamide The 2-keto-l-adamantaneacetyl chloride obtained as reported in Example 1 was dissolved in dry ether (50 ml.) and ammonia was passed into the stirred solution for 1 hour at room temperature. After removal of the ether the residue was partitioned between water (50 ml.) and chloroform (50 ml.) and the aqueous phase was extracted with two further 50 ml. portions of chloroform. The combined chloroform extract was washed with 10 percent W./v. sodium carbonate solution (50 ml.), then with two 50 ml. portions of water, dried over magnesium sulfate and evaporated to give the expected 2-keto-1-adamantaneacetamide product as a pale solid (yield ca. 80 percent). It was crystallized from acetone/n-hexane to give a puri fied product as the monohydrate (2.68 grams, 68 percent), M.P., 120-125 C.

Calc. for C H NO -H O (percent): C, 64.10; H, 8.45; N, 6.24. Found (percent): C, 64.70; H, 8.67; N, 6.20.

EXAMPLE 3 Z-aminol-adamantaneacetamide A solution of 2-keto-l-adamantaneacetamide monohydrate prepared as reported in Example 2 (0.96 gram; 0.0046 mole) in ethanol (50 ml.) was heated to reflux and refluxed for minutes while ammonia gas was passed into the solution; the solution was then cooled to room temperature and saturated with ammonia. After standing overnight the solution was hydrogenated over 10 percent palladium on carbon for 24 hours at room temperature and lb./sq. in. pressure and for a further 6 hours at around 60 C. and 60 lb./ sq. in. The catalyst was filtered off, and the filtrate was evaporated to dryness under vacuum. A solution of the residue in chloroform (10 ml.) was extracted with two m1. portions of dilute hydrochloric acid. The bulked extract Was basified and reextracted with two 10 ml. portions of chloroform and the chloroform extract was dried over magnesium sulfate and evaporated to give the desired 2-amino-1-adamantaneacetamide as a white solid (0.39 gram; percent). It was crystallized from chloroform-light petroleum; the product so obtained was shown by melting point, mixed melting point and infrared spectrum procedures to be identical with a sample prepared from Z-amino-l-adamantaneacetic acid (Examples 10, 11, and 12 hereinbelow).

8 EXAMPLE 4 5,7-diazatetracyclo(7.3.1.1 .0 )tetradecan-G-one '2-amino- 1 adamantaneacetamide (3.3 grams; 0.0158 mole) was added in small portions to a stirred solution of bromine (0.95 ml., 0.019 mole) in -10 percent w./v. sodium hydroxide (40 m1.) at 0-5 C. After stirring for 1 hour at -0-5 C., and 1 hour at 70- C., the solid was filtered off, washed with water (20 ml.), dilute HCl (20 ml.) and water (20 m1.) again, and crystallized from dimethylformamide to give 5,7 diazatetracyclo- (7.3.1.1 0 )tetradecan-6-one (1.83 grams; 56 percent), M.P. 310-320" (dec.).

Calc. for C H N O (percent): C, 69.86; H, 8.80; N, 13.58. Found (percent): C, 69.50; H, 8.84; N, 13.49.

EXAMPLE 5 Z-ketol-adamantanemethylamine Z-keto-l-adamantaneacetamide prepared as described in Example 2 (2.07 grams; 0.010 mole) was added in small portions to a stirred solution of bromine (0.6 ml., 0.012 mole) in 12 percent w./v. sodium hydroxide (20 ml.) at 0 C. The mixture was stirred for 1 /2 hours at 0 C., then 30 minutes at 70-80 C., cooled and extracted with ether (three 20-milliliter portions). The extract was washed with water '(10 ml.), dried over magnesium sulfate, and treated with ethanolic hydrochloric acid. The precipitate was crystallized from ethanol-ether to give 2- keto 1 adamantanemethylamine as the hydrochloride (1.2 grams; 56 percent), M.P. 214-220 C.

Calc. for C H NQHCI (percent): C, 61.25; H, 8.41; N, 6.50. Found (percent): C, 60.85; H, 8.33; N, 6.64.

EXAMPLE 6 2-amino-l-admantanemethylamine Ammonia was passed into a refluxing solution of 2- keto 1 adamantanem'ethylamine hydrochloride (0.43 gram; 0.002 mole), prepared as reported in Example 5, in ethanol ('25 ml.) for 30 minutes. After cooling and saturating with ammonia the solution was hydrogenated at room temperature and atmospheric pressure over -10 percent palladium on carbon (0.1 gram) for 4 hours. The catalyst was filtered off and the filtrate was concentrated under vacuum, acidified with ethanolic HCl and diluted with ether to give 2-amino-l-adamantanomethylamine as the dihydrochloride (0.16 gram; 32 percent), M.P. 300- 310 C. (dec.).

Calc. for C H N -2HCl (percent): C, 52.18; H, 8.76; N, 11.06. Found (percent): C, 52.10; H, 8.62; N, 10.60.

EXAMPLE 7 '2-keto- I-acety1- l-adamantanemthylamine 2-ket0-1-adamantanemethylamine hydrochloride (0.50 gram; 0.0023 mole), prepared as described in Example 5, was dissolved in water (5 ml.), and the solution was basified and extracted with chloroform (two S-milliliter portions). After drying over calcium sulfate, the extract was treated with acetic anhydride (3 ml.) and heated under reflux for 1 hour, then evaporated to dryness. The solid residue was washed with water and crystallized from chloroform-light petroluem to give 2-keto-N-acetyl-1- adamantanemethylamine (0.31 gram; 61 percent), M.P. 122l24 C.

Calc. for C H NO (percent): C, 70.55; H, 8.66; N, 6.33. Found (percent): C, 70.60; H, 9.10; N, 6.25.

EXAMPLE 8 1- acetamid omethyl -2-aminoadam antane An ethanolic solution of the 2-keto-N-acety1-1-adamantanemethylamine prepared as reported in Example 7 was subjected to reductive amination with ammonia and hydrogen over 10 percent palladium on carbon at about 60 p.s.i. to give Z-aminoN-acetyl-l-adamantanemethylamine, which upon dehydration yields 6-methyl-5,7-diazatetracyclo(7.3.1.1 )tetradec-S-ene.

EXAMPLE 9 Z-methylamino-l-adamantaneacetic acid A solution of '2-keto-l-adamantaneacetic acid (6.24 grams; 0.030 mole) in a 33 percent w./v. solution of methylamine in ethanol (150 ml.) was hydrogenated at atmospheric pressure over 10 percent palladium on charcoal (0.5 gram) for 6 hours. After removal of the catalyst the filtrate was evaporated and the residue crystal- 'lized from ethanol-ether to give Z-rnethylamino-l-adamantaneacetic acid (6.8 grams; 100 percent), M.P., 143- '144" C.

Calc. for C H NO (percent): C, 69.92; H, 9.48; N, 6.27. Found (percent): C, 70.40; H, 9.49; N, 6.55.

EXAMPLE 10 Z-(benzyloxycarbonylamino)-1-adamantaneacetic acid Benzyl chloroformate (4.1 grams; 0.024 mole) was added dropwise to a stirred, ice-cold solution of 2-aminol-adamantaneacetic acid hemihydrate (4.1 grams; 0.021 mole) in 2 N sodium hydroxide 10 ml.), maintaining the pH at about 10-11 by addition of further 2 N sodium hydroxide (10 ml.). After stirring for a further 40 minutes at 0-5 C, the reaction mixture was washed with ether (20 ml.), acidified with concentrated hydrochloric acid and extracted with ethyl acetate (three 25-milliliter portions). The extract was washed with water (10 ml.), dried over magnesium sulfate, and evaporated to give, on addition of light petroleum, 2-(benzyloxycarbonylamino)-1-adamantaneacetic acid (5.8 grams; 85 percent), M.P. 134-135 C., recrystallized from acetone-hexane, M.P., 136-l3'8 C.

Calc. for C H NO (percent): C, 69.95; H, 7.34; N, 4.08. Found (percent): C, 70.25; H, 7.46; N, 4.17.

EXAMPLE 1 1 2- (benzyloxycarbonylamino -l-adamantaneacetamide To a stirred ice-cold solution of Z-(benzyloxycarbonylamino) 1 adamantaneacetic acid (5.75 grams; 0.0168 mole) and triethylamine (2.44 1111., 0.0175 mole) in dry toluene (100 ml.) was added dropwise a solution of ethyl chloroformate (1.67 ml., 0.0175 mole) in dry toluene (10 ml.). After stirring for 1 hour at 0 C., the white solid was filtered 01f, ammonia was passed into the filtrate for 1 hour, and the mixture was kept for 16 hours at room temperature. The solvent was removed under vacuum and a solution of the residue in ethyl acetate (200 ml.) was washed successively with 5 percent W./V. sodium carbonate (100 ml.) dilute hydrochloric acid (100 ml.), and water (50 ml.) and crystallized by concentration and addition of light petroleum to give 2- (benzyloxycarbonylamino) 1 adamantanacetamide (4.3 grams; 75 percent), M.P., 160-1 63 C., recrystallized from acetone-hexane, M.P., 166-168 C.

Calc. for C H N O (percent) C, 70.15; H, 7.65; N, 8.18. Found (percent): C, 70.80; H, 7.53; N, 8.15.

EXAMPLE 12 2-aminol-adamantaneacetamide A solution of 2-(benzyloxycarbonylamino)-1-adamantaneacetamide (5.4 grams; 0.0158 mole) in ethanol (150' ml.) was hydrogenated at room temperature and 30 lb./sq. in. pressure over percent palladium on carbon (1.0 gram) for 1 hour. The catalyst was filtered off and the filtrate evaporated to give Z-amino-l-adamantaneacetamide (3.4 grams; 100 percent), M.P., 138-140 C., recrystallized from chloroform-light petroleum, M.P. 156158 C.

Calc. for C H N O (percent): C, 69.19; H, 9.68; N, 13.45. Found (percent): C, 69.10; H, 9.64; N, 13.20.

EXAMPLE l3 5,7-diazatetracyclo (7 .3.1. 1 .0 )tetradecan-6-one Z-amino-l-adamantaneacetamide, obtained as reported in Example 12, was reacted in the same manner as described in Example 4 to obtain 5,7-diazatetracyclo (7 3. l 1 .0 )tetradecan-6-one.

Other compounds representative of the present invention and prepared in accordance with the foregoing teachings and examples include the following.

EXAMPLES 14-17 1x,3,5,7-tetramethyl-2-keto-l-adamantaneacetic acid is converted to a,3,5,7-tetramethyl-2-keto 1 adamantane acetyl chloride, which in turn is converted to u,3,5,7-tetramethyl-2-keto 1 adamantancacetamide. Holfmann degradation of this last named compound yields u,3,5,7- tetramethyl-2-keto-l-admanatanemethylamine which is reductively aminated with amomnia to yield a,3,5,7-tetramethyl-2-amino-l-adamantanemethylamine.

EXAMPLES 18-21 a,n-hexyl-5-isopropyl-2-keto-l-admantaneacetic acid is converted to a-n-hexyl-5-isopropyl-2-keto-l-adamantaneacetyl bromide, which in turn is converted to a-n-hexyl-S- isopropyl-Z-keto-l-adaman-taneacetamide. Hoffmann degradation of this last named compound yields u-n-hexyl-5- isopropyl-Z-keto-l-adamantanemethylamine which is reductively aminated with methylamine to yield a-n-hexyl- 5-isopropyl-2-methylarnino-adamantanemethylamine.

EXAMPLES 22-25 3,5-di-n-propyl-2-keto-l-adamantaneacetic acid is converted to 3,S-di-n-propyl-Z-keto-l-adamantaneacetyl chloride, which in turn is converted to 3,5-di-n-propyl-2-ketol-adamantaneacetamide. Hoffmann degradation of this last named compound yields 3,5-di-n-propyl-2-keto 1- adamantanemethylamine which is reductively aminated with isopropylamine to yield 3,5-di-n-propyl-2-(isopropylamino) -l-adamantanemethylamine.

EXAMPLES 26-29 EXAMPLES 3 O-3 2 a,3,5,7-tetramethyl-2-keto-l-adamantanemethylamine is acylated by reaction with acetic anhydride to yield 11,3,5, 7-tetramethyl-2-keto-N-acetyl-1 adamantanemethylamine which in turn is reductively aminated with ammonia to obtain 11,3,5,7-tetramethyl-Z-amino-N-acetyl 1 admantanemethylamine. Cyclization of this last named compound yields 1,3,6,8,11-pentamethyl-5,7 diazatetracyclo (7.3.1.1 .0 )tetradec-S-ene.

EXAMPLES 33-35 u-n-hexyl-5-isopropyl-2-keto-l-admanatanemethylamine is acylated by reaction with propionic anhydride to yield a-n-hexyl-5-isopropyl-2-keto-N-propionyl-1 adamantanetanemethylamine which in turn is reductively aminated with ammonia to obtain a-n-hexyl-5-isopropyl-2-amino- N-propionyl-l adamantanemethylamine. Cyclization of this last named compound yields 8-n-hexyl-1-isopropyl-6- ethyl-5 ,7 -diazatetracyclo (7.3 .1.1 .0 )tetradec-S-ene.

EXAMPLES 3 6-3 8 3,5-di-n-propyl-2-keto-1 adamantanemethylamine is acylated by reaction with butyric anhydride to yield 3,5-

di-n-propyl-2-keto-N-butyryl-1 adamantanemethylamine which in turn is reductively aminated with ammonia to obtain 3,5-di-n-propyl-Z-amino-N-butyryl 1 adamantanemethylamine. Cyclization of this last named compound yields 3,6,11 tri n propyl 5,7 diazatetracyclo (7.3.l.1 .0 )tetradec-S-ene.

EXAMPLES 39-41 a-n-propyl-3,5,7-triethyl-2-keto-1 adamantanemethylamine is acylated by reaction with acetic anhydride to yield oc-n-propyl-3,5,7-triethyl-Z-keto-N-acetyl-1 adamantanemethylamine, which in turn is reductively aminated with ammonia to obtain a-n-propyl-3,5,7-triethyl-2-amino-N- acetyl-l-adamantanemethylamine. Cyclization of this last named compound yields 8-n-propyl-1,3,1l triethyl 6- methyl-5,7-diazatetracyclo (7.3 l 1 .0 tetradec-S-ene.

EXAMPLES 42-43 05,3,5,7-tetramethyl-2-keto-1 adamantaneacetamide is reductively aminated by reaction with n-propylamine to yield a,3,5,7-tetramethyl-2-(n-propylamino)-l adamantaneacetamide, which under Hofimann rearrangement conditions cyclizes to 1,3,8,11-tetramethyl-5-n propyl 5,7- diazatetracyclo (7.3 1.1 .0 )tetradecan-6-one.

EXAMPLES 44-46 a-n-hexyl-5-isopropyl-2-keto-l-adamantaneacetic acid is reductively aminated by reaction with ammonia to yield a-n-hexyl-5-isopropyl-Z-amino-1 adamantaneacetic acid, the amino group of which is protected by reaction with benzyl chloroformate. The amino-protected compound is then converted through the acetyl chloride to the amide and the amino-protecting group removed. As a result of these operations, there is obtained a-n-hexyl-5-isopropyl- 2-an1ino-l-adamantaneacetamide, which under Hofimann rearrangement cyclizes to 8-n-hexyl-l-isopropyl-5,7-diazatetracyclo (7.3 .1.1 .0 )tetradecan-6-one.

EXAMPLES 47-48 3,S-di-n-propyl-Z-keto-l-adamantaneacetamide is reductively aminated by reaction with ammonia to yield 3,5-din-propyl-Z-amino-l adamantaneacetamide, which under Hoffmann rearrangement conditions cyclizes to 1,3-di-npropyl-5,7-diazatetracyclo(7.3.1.1 .0 )tetradecan 6- one.

EXAMPLES 49-51 a-n-propyl-3,5,7-triethyl-2-keto 1 adamantaneacetic acid is reductively aminated by reaction with methylamine to yield u-n-propyl 3,5,7 triethyl-Z-(methylamino)-ladamantaneacetic acid, the amino group of which is protected by reaction with 'benzyl chloroformate. The aminoprotected compound is then converted through the acetyl halide to the amide and the amino-protecting group removed. As a result of these operations, there is obtained a-n-propyl-3,5,7-triethyl 2 (methylamino)-l-adamantaneacetamide, which under Hoifmann degradation conditions cyclizes to 8-n-propyl-l,3,ll-triethyl 5 methyl-5,7- diazatetracyclo(7.3.l .1. .0 )-tetradecan-6-one.

The ultimate products of the present invention, compounds of Formula I and II, are useful as analgesics and as local anaesthetics in warm-blooded animals. The compounds can be administered in any of several routes, and can be formulated to facilitate administration, in liquid or solid formulations such as tablets, pills, capsules, granules, powders, oral solutions or suspensions, and the like. The exact concentration of the present compound or compounds in the formulation is not critical, it being necessary only that an appropriate dosage of the compound or compounds be supplied to the animal being treated. In general, activity is obtained at rates of from 1 to 200 mg./kg. or more, depending upon the particular compound chosen, particular animal administered to, mode of administration, and other factors. Such administration can be made on one occasion to relieve a particular situation, or can be made on several occasions over a given period of time, such as daily, to achieve a continuing therapeutic effect. In a representative evaluation, a group of 5 mice was dosed intraperitoneally with a carboxymethylcellulose sus pension as indicated supra and at a rate of mg./kg. Thirty minutes later the mice were challenged with 0.5 percent acetic acid and observed for writhing normally resultant from such challenge. Four mice of the treated group were completely protected from writhing during the thirty minutes following administration. In a control group of 5 mice likewise challenged with 0.5 percent acetic acid, all exhibited writhing, there being a total of 85 writhes in the first 15 minutes following challenge and a total of 50 additional writhes in the next 15 minutes.

The starting materials to be employed in accordance with the present invention:

In a representative oxidation, a solution of potassium permanganate (4.2 grams; 0.027 mole) in 85 milliliters of water was added gradually to a well-stirred suspension of 2-hydroxy-l-adamantaneethanol (3.0 grams; 0.0143 mole) in 6.6 milliliters of a 10 percent aqueous solution of sodium hydroxide. After the addition which was carried out at room temperature, a deep green color persisted, and another solution of potassium permanganate (4.2 grams; 0.027 mole, in 85 milliliters of water) was added gradually. Thereafter, the reaction mixture was heated mildly on a steambath for about 3 hours, after which it was permitted to cool and held overnight at room temperature. The reaction mixture was then filtered from manganese dioxide and the precipitate washed with water. The combined filtrate and Wash were extracted with ether. The aqueous layer was then acidified with dilute sulfuric acid, causing precipitation of the desired Z-ketO-I-adamantaneacetic acid product. This product was extracted with ether, and the resulting ether solution washed with water, dried over magnesium sulfate, and the solution evaporated under subatmospheric pressure. The resulting product was crystallized from a mixture of ether and n-hexane to yield 2.5 grams of 2-keto-l-adamantaneacetic acid, M.P. 146 C.

Analysis, Calc. (percent): C, 69.21; H, 7.75. Found percent): C, 69.47; H, 7.83. The product was converted in standard procedures to its oxime, M.P. l53-155 C.

Analysis, Calc. (percent): C, 64.57; H, 7.65; N, 6.27. Found (percent): C, 65.10; H, 7.60; N, 6.10.

All of the Z-hydroxy-l-adamantaneethanol compounds are prepared in the same manner described for the preparation of 2-hydroxy-l-adamantanethanol in pending wherein:

(1) each R represents hydrogen or C -C loweralkyl, the sum of the number of carbon atoms in all three R groups being not greater than 6; (2) each R independently represents hydrogen or straight-chain C -C alkyl; and (3) each R" independently represents hydrogen or C -C loweralkyl; and their pharmaceutically acceptable acid addition salts. 2. The compound of claim 1 wherein each R and R represents hydrogen and R represents methyl.

3. The compound selected from the group consisting of the compounds of the formula wherein:

(1) each R represents hydrogen or C -C loweralkyl, the sum of the number of carbon atoms in all three R groups being not greater than 6; (2) each R independently represents hydrogen or straight-chain C -C alkyl; and (3) each R" independently represents hydrogen or C -C loweralkyl. 4. The compound of claim 3 wherein each R, R, and R" represents hydrogen.

References Cited UNITED STATES PATENTS 3,346,452 10/1967 Carney et al 16765 ALEX MAZEL, Primary Examiner 30 R. V. RUSH, Assistant Examiner US. Cl. X.R.

260-468 C, 514 B, 544 L, 557 R, 561 R, 563 R; 424-232, 251

} mg UN TED STATES PATENT ()FFICE ERTIFIATE OF QGRRECNON Patent: No. 5,64 556 Dated February 22 1972 lnventofls) Jiban Kumar Chakrabarti et al.

It is certifiecl that. error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

At each of the following locations:

each of the formulae at column 1, lines 16-25 each of the formulae at column 1, lines AIS-55; the formula at column 5, lines 62-70; the formula at column 6, lines 5-12; the formula at column 6, lines 66-75;

the formula in Claim 1; and the formula in Claim the left-hand. portion of the respective formula comprises in part the following unit:

whereas the structure and numbering of this unit at each of the specified locations should he:

UNETED STATES PATENT OFFICE CER'NFECATE OF CORREC'NON Patent No. 5,6,556 I Dated Februar 22, 1972 Inventor(s) Jiban Kumer Chahreberti et all It is certified that errorappears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

At each of the following locations each of the formulae at column 1, lines 55-65; the formula at column 2, lines 1-9;

the formula at column 2, lines 10-18;

the formula at column 2, lines 6-52;

the formula at column 2, lines 56-65;

the formula at column 12, lines 17-28; and. the formula. at column l2, lines Bl-hfi,

the left-hand portion of the respective formula comprises in part the followingu'nit:

whereas the structure and numbering of this unit at each of the specified locations should be:

$222 3 TE STATES PATENT UFFEQE CERTIFICATE or ECIN Patent L 55 Dated February 22, 1.972

Inventor(s) Jiban Kumar Chakrabarti et al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

ron In column 1., line 28, "amantanopyrimidino" should be spelled --amenta.nopyrimidine-.

In columns 3 &, the middle formula in the column titled "Section III" should be :a' o i H CH 0: NH 2 3 Ad \NHR" also in column 3, line 56, "units" should be -unit--, and in column line 56, "reatcion should be -reaction.

In column 7, line 65, between "two" and "ml.", there should be inserted the number --lO--.

In column 8, line about 52, "adamantanemthylamine" should be spelled -ada.mentenemethylamine-; also in column 8, line 62, "petroluem" should be spelled --petroleum--; and in column 8, line 65, the formula "C etc. should be --C etc.

In column 1.0, line 2, the first set of superscripts, i.e. should be: --s,11--; also in column 10, line 25, "admantaneacetic" should be spelled --a,da.ma.nta.neacetic"; and in column 10, line 67', the first word unit, "tanemethylamine" should be -methylam1i1ne---.

In column ll, line 59, the first set of superscripts,

i.e., "9,11", should be L Signed and sealed this 21st day of November 1972. J

(SEAL) Attest:

EDWARD M.FLETCHER,JR., ROBERT GOiI'TSCHALK Attesting Officer Commissionerof Patents 

